This invention is in the field of swimming pool structures.
It is customary to build swimming pools by erecting a sidewall or sustaining wall around the pool within an excavation and to then provide a liner of flexible water proof sheet metal to hold the water in the pool. It has also been proposed to construct such sidewalls of modular units comprising sheets of metal or other suitable material bent to provide flanges at their ends and/or top and bottom edges to rigidify the modules. However, such modules must be constructed to the desired curved shape where curves are part of the pool design and this involves considerable manufacturing time and expense (see U.S. patents to Lucchesi U.S. Pat. No. 3,015,191, Ross U.S. Pat. No. 3,059,243 and Miccio U.S. Pat. No. 3,094,709). The above patents all include one or more upper or lower flanges to define modules of more or less pan shape, which are bolted together. However, such construction involves the manufacture of different size and shaped pans for different shaped pools. It has also been proposed to construct storage tanks of modular plates having reinforcing flanges at the edges of certain of the plates with some of the area of each module stepped outwardly, so that the adjacent module edge would seat within the step and provide a somewhat smooth surface (see U.S. Pat. No. 1,076,382). Such structure is also shown in U.S. Pat. No. 2,123,035. It has also been proposed to construct containers of modular units wherein the overlapping edges of adjacent units are provided with nested depressions to receive fasteners.
All of the previous proposals, however, were for special purposes and designed solely for that particular purpose and not clearly adaptable to swimming pools.